heif: declare read support for HIF

image/heif MIME type uses following three file extensions:
heif, heic, hif.

Adding HIF into plugin's list.

src/imageformats/heif.cpp

@@ -1465,6 +1465,14 @@ QImageIOPlugin::Capabilities HEIFPlugin::capabilities(QIODevice *device, const Q
         return format_cap;
     }
 
+    if (format == "hif") {
+        Capabilities format_cap;
+        if (HEIFHandler::isHeifDecoderAvailable()) {
+            format_cap |= CanRead;
+        }
+        return format_cap;
+    }
+
     if (format == "hej2") {
         Capabilities format_cap;
         if (HEIFHandler::isHej2DecoderAvailable()) {

src/imageformats/heif.json

@@ -1,4 +1,16 @@
 {
-    "Keys": [ "heif", "heic", "hej2", "avci" ],
+    "Keys": [
-    "MimeTypes": [ "image/heif", "image/heif", "image/hej2k", "image/avci" ]
+        "heif",
+        "heic",
+        "hif",
+        "hej2",
+        "avci"
+    ],
+    "MimeTypes": [
+        "image/heif",
+        "image/heif",
+        "image/heif",
+        "image/hej2k",
+        "image/avci"
+    ]
 }